Data commit

Task/ABC-problem/Picat/abc-problem.picat

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+go =>
+  test_it(check_word),
+  test_it(check_word2),
+  nl.
+
+% Get all possible solutions (via fail)
+go2 ?=>
+  test_version(check_word2),
+  fail,
+  nl.
+go2 => true.
+
+%
+% Test a version.
+%
+test_it(Pred) =>
+  println(testing=Pred),
+  Blocks = findall([A,B], block(A,B)),
+  Words = findall(W,word(W)),
+  foreach(Word in Words)
+     println(word=Word),
+     ( call(Pred,Word,Blocks) ;  println("Cannot make word.")),
+     nl
+  end,
+  nl.
+
+%
+% Picat style: Using nth/3 for getting the chars
+%
+check_word(Word, Blocks) =>
+  WordC = atom_chars(Word), % convert atom to string
+  WordLen = length(WordC),
+  X = new_list(WordLen),
+  Pos = new_list(WordLen),
+  foreach(I in 1..WordLen)
+    % find a character at the specific position
+    nth(X[I],Blocks,XI),
+    nth(Pos[I],XI, WordC[I])
+  end,
+  alldiff(X), % ensure unique selection
+  foreach(I in 1..WordLen)
+    println([WordC[I], Blocks[X[I]]])
+  end,
+  nl.
+
+%
+% Prolog style (recursive) version using select/3.
+% (where we don't have to worry about duplicate blocks)
+%
+check_word2(Word, Blocks) :-
+  pick_block(atom_chars(Word),Blocks,[],X),
+  println(X).
+
+pick_block([], _,Res,Res).
+pick_block([C|WordRest], Blocks, Res1,[Block|Res]) :-
+  % pick (non-deterministically) one of the blocks
+  select(Block,Blocks,BlocksRest),
+  membchk(C,Block),
+  pick_block(WordRest,BlocksRest,Res1,Res).
+
+%
+% alldiff(L):
+%   ensure that all elements in L are different
+%
+alldiff([]).
+alldiff([_]).
+alldiff([H|T]) :-
+   neq(H,T),
+   alldiff(T).
+
+neq(_,[]).
+neq(X,[H|T]) :-
+  X != H,
+  neq(X,T).
+
+% The words to check.
+word(a).
+word(bark).
+word(book).
+word(treat).
+word(common).
+word(squad).
+word(confuse).
+word(auto).
+word(abba).
+word(coestablishment).
+word(schoolmastering).
+
+% The blocks
+block(b,o).
+block(x,k).
+block(d,q).
+block(c,p).
+block(n,a).
+block(g,t).
+block(r,e).
+block(t,g).
+block(q,d).
+block(f,s).
+block(j,w).
+block(h,u).
+block(v,i).
+block(a,n).
+block(o,b).
+block(e,r).
+block(f,s).
+block(l,y).
+block(p,c).
+block(z,m).